Method for manufacturing hollow structure for breathing mask

ABSTRACT

A method for producing a filled hollow structure includes producing an open hollow structure of a first material, positioning the open hollow structure on a tool adapted to hold the open hollow structure, filling the open hollow structure with a filler medium, and closing the filled open hollow structure with a second material. A hollow structure may be produced by such method, and a tool may be structured to perform such method.

CROSS-REFERENCE TO RELATED APPLICATION

This application is the U.S. national phase of International.Application No. PCT/EP2007/009478, filed Oct. 31, 2007, which designatedthe U.S. and claims the benefit of European Patent Application No. EP 0710 0927.8, filed Jan. 22, 2007, each of which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The invention relates to a method for producing a hollow structure andmore particularly to a method for producing a closed and filled hollowstructure. Furthermore, the present invention relates to a hollowstructure and more particularly to a closed and filled hollow structureobtainable by a method according to the present invention as well as toa tool for producing such hollow structure and/or for performing arespective method.

BACKGROUND OF THE INVENTION

Hollow structures are known in the prior art, for example, in the fieldof face masks for delivering breathable air to a patient. In such facemasks, hollow cushions are used for providing contact zones forcontacting the face of the user in order to avoid dents and to improvewearing comfort of the user. Furthermore, such structures are used as asealing structure for sealing the mask interior from the exterior in thecontact region where the mask rests on a user's face.

A disadvantage of hollow structures known in the art is that they arecomplicated to manufacture and a number of manual manufacturing steps isoften necessary. Moreover, such hollow structures are either not closed,i.e., open, or are closed in an ineffective and/or complicated manner.

In particular, it is known to fill a mask cushion with silicone or gelwherein the hollow structure is closed by use of a silicone adhesive.

The solutions known in the prior art are in particular, not easy tohandle, not durable, complicated and expensive to manufacture, notsuitable for automating, not bio-compatible as well as optically andhygienically objectionable.

SUMMARY OF THE INVENTION

One aspect of the present invention relates to a method for producing ormanufacturing a hollow structure and particularly a filled hollowstructure which overcomes the deficiencies of the prior art. Moreparticularly, an aspect of the present invention relates to a method formanufacturing the hollow structure which is easy and efficient to carryout, which can be automated, and which provides for a durable as well asan optically and hygienically improved hollow structure. Moreover, anaspect of the present invention relates to a tool for producing a hollowstructure as well as an improved hollow structure.

Another aspect of the present invention relates to a method forproducing a filled hollow structure comprising producing an open hollowstructure of a first material, e.g., a structure having a hollow orhollow area such as a pocket or a cavity wherein at least a portion ofthe hollow is open towards the outside of the structure, positioning theopen hollow structure in or on a tool adapted to hold the open hollowstructure, at least partially filling the open hollow structure with afiller medium, and closing the filled open hollow structure with asecond material. The filled open hollow structure may be closed byclamping jaws that are adapted to provide a cavity into which theportions of the hollow structure to be closed extend. In this context,it is to be noted that clamping jaws as referred to in the presentapplication are not limited to perform a pivoting motion towards oneanother but may also or alternatively clamp via a linear motion or thelike.

According to the present invention a filler medium is preferablyconsidered to be a medium being non-releasably contained in a structure,i.e. a medium which is to stay in a structure, such as a hollowstructure. According to the present invention a filled hollow structureonce closed is preferably considered to non-releasably contain thefiller medium.

The cavity may be filled with a second material adapted to close (and/orseal) the open hollow structure. In an embodiment, before and/or whilefilling the cavity with the material for closing and/or sealing the openhollow structure, pressure may be applied to the cavity and/or by theclamping jaws to the opening of the hollow structure in order tosecurely close and/or seal the hollow structure. This arrangement mayprevent the material for closing and/or sealing the open hollowstructure from entering the open hollow structure.

According to an embodiment, the sequence of method steps may be changed,e.g., the open hollow structure may be provided with a connection and isfirst closed and/or sealed, as discussed above, and subsequently atleast partially filled with a filler medium through the connection. Inan embodiment, the connection may act as a one way valve so that theconnection does not need to be closed or sealed after the filling step.Also, the connection may be closed and/or sealed after the filling step.According to a further embodiment, the open hollow structure may befirst closed and/or sealed. A vacuum may be applied to the hollowstructure and the structure may be filled with a filler medium. Theapplication of vacuum and the filling may be carried out subsequentlyand/or simultaneously. The application of a vacuum may be advantageousin case, e.g., a viscous gel is used as a filler medium.

In an embodiment, the open hollow structure may be made of a firstmaterial and a second material may be used for closing the open hollowstructure. One or both of the first and second materials may be anelastic material.

The hollow structure may be made of a flexible first material, e.g., aplastic or synthetic material such as an elastomer material or amaterial comprising elastomer components. For example, the hollowstructure may be made of silicone such as liquid silicone rubber (LSR),or thermoplastic elastomer (TPE). In an embodiment, an open hollowstructure may be an injection molded plastic skin, e.g., made ofsilicone or a liquid silicone rubber (LSR). In an embodiment, the hollowstructure may include a first portion to be filled by filler medium, asecond portion which is constructed as a connection structure ortransition portion between the first portion and a third portion whichis adapted for filling and closing or sealing the hollow structure.Alternatively, the second portion may be optional and the hollowstructure may comprise only the first and the third portions.

The third section of the hollow structure according to an embodiment,i.e., the area for filling and sealing the hollow structure, may bedesigned as or include a bi-stable membrane which may assume twopositions, e.g., a first position in which the hollow structure is openfor filling the structure and a second position in which the hollowstructure is closed for closing and/or sealing.

The geometry of the hollow structure in the third section may becircular, oval, non-circular, linear, etc. In an embodiment, the thirdsection may include two opposite flattened areas which are adapted toclose the hollow structure when abutting each other.

Furthermore, the hollow structure may include thin or skin-like outerwalls which may have, according to embodiments, a differing wallthickness and/or topography. According to an embodiment, the open hollowstructure may be described as having a generally tube-like form whichhas been put over itself resulting in a hollow structure having an innerwall and an outer wall which merge at one end of the structure via abottom or transition wall and which is open at the other end of thestructure. However, it is to be understood that the tube-like basic formas referred to above is not restricted to one diameter or a circularform but may comprise different cross sections, diameters, wallthicknesses, etc. In an embodiment, when used in the field of face masksfor delivering breathable air to a patient, the hollow structure mayhave a generally tubular ring-like form with a generally triangularcross-section, particularly at its bottom or transition wall serving asa contact zone for resting on a patient's face. In an embodiment, whenused in the field of face masks for delivering breathable air to apatient, the wall thickness may vary and may lie in the range of about0.1 mm to about 7 mm. In an embodiment, the hardness of the hollowstructure may lie in the range from about 1 to 80 Shore A, e.g., about20 to 60 Shore A or in the range of about 3 to 10 Shore A or about 5Shore A or 40 Shore A. The hardness may depend on the spring and dampingproperties of the material and the ability to be easily demolded.

The filler medium which is filled into the open hollow structure mayinclude a fluid, i.e., a gaseous, dispersible and/or liquid fluid, anexpandable fluid, a foam, a powder and/or gel. According to embodiments,a mixture of the above media may be used, e.g., two gels of differenthardness or viscosity.

The second material used for closing the open hollow structure may besuitable to seal the opening of the open hollow structure in a liquidand/or gas tight manner. In an embodiment, the fluid may include thesame material as that from which the open hollow structure is made.According to an embodiment, the material for closing the open hollowstructure may be silicone or liquid silicone rubber. According to anembodiment, the second material used for closing the filled hollowstructure is not a silicone glue or is not a silicone adhesive.

The method according to an embodiment of the present invention mayfurther include curing the material for closing the open hollowstructure. Such curing may involve, depending on the conditions and thematerials used, e.g., the addition or removal of energy, application oftemperature, i.e., heat or cold, radiation, e.g., UV-light, the additionof further substances and/or time factors, i.e., waiting time, etc.,foaming, and/or initiation of crystallization. During curing, the formor geometry of the closed or sealing area may be controlled, e.g., bythe clamping jaws and the respective cavity.

In an embodiment, the open hollow structure may be held on the tool forholding the open hollow structure by the provision of a firm fit by theapplication of compressed air and/or vacuum. Also, the closed hollowstructure may be removed from the tool by the use of compressed airand/or vacuum.

In an additional step, a vacuum may be applied to the hollow before thefiller medium is inserted into the hollow. The application of the vacuumto the hollow sucks air out of the hollow before the filler medium isinserted into the hollow so that an improved, e.g., void free, fillingof the hollow may be achieved.

In a further additional step, a vacuum may be applied to the hollow andthe filler medium after the open hollow structure has been filled withthe filler medium. This step may improve the optical and hygienicallyappearance of the filled hollow structure as well as its mechanicalproperties by reducing or eliminating voids occurring in the fillermedium and by providing a desired shape or structure to the hollowstructure.

The material for closing the open hollow structure may be, according toan embodiment, applied into the cavity provided by the clamping jawsunder pressure. Further, the clamping jaws may be heated for curing thematerial for closing the open hollow structure.

According to an embodiment, the method according to an embodiment of theinvention may further include coating the hollow structure and/or thefiller medium in the hollow, particularly in order to improve durabilityand/or optical and/or hygienically properties. According to a furtherembodiment, the coating step may be performed after applying a vacuum tothe hollow and the filler medium, e.g., in order to provide a desiredshape, and eliminate voids in the filler medium, etc.

According to an embodiment, the hollow structure may include aconnection structure adapted to connect the hollow structure to furtherstructures. For example, according to an embodiment, the hollowstructure may form part of a face mask and thus may be suitable to beconnected with other structures, to fulfill other or additionalfunctions, and/or to additionally form other structures in order to formsuch a mask.

According to a further embodiment, the hollow structure may include aconnection adapted to allow a vacuum to be applied to the hollow. Theconnection allows the vacuum to shape the structure and to fix therespective shape. In an embodiment, the connection may be closed so thatthe vacuum may be maintained inside the hollow structure.

The filler medium may be suitable to store heat and/or cold. Accordingto a further embodiment, the filler medium may be structure to hardenand/or soften if certain predetermined conditions are met. In anembodiment, the filler medium may harden and/or soften upon a triggersignal, such as a signalization signal, or upon the application of heator cold, etc.

Another aspect of the present invention relates to a hollow structureproduced by a method according to an embodiment of the present inventionas well as a tool for producing such hollow structure and/or forperforming a method according to an embodiment of the present invention

Another aspect of the invention relates to a hollow structure includingan inner wall, an outer wall spaced from the inner wall to define ahollow between the inner and outer walls, a bottom wall that couples theinner and outer walls, and first and second portions that define aclosable opening into the hollow. The first portion is coupled to theouter wall by a membrane that allows the first portion to move between(1) a first, opened position in which the first portion is spaced fromthe second portion to allow access to the hollow through the opening,and (2) a second, closed position in which the first portion abuts thesecond portion to close the opening.

Another aspect of the invention relates to a tool for producing a hollowstructure. The tool includes a rotatable table providing a plurality ofworking positions and one or more fixed working stations each adapted toperform one or more manufacturing operations. Each working positionincludes a working tool adapted to hold a respective hollow structure inan operative position. The table is adapted to be rotated so that eachworking position may pass by the one or more fixed working stations forperformance of one or more manufacturing operations on the respectivehollow structure.

According to an embodiment, the hollow structure may constitute acushion to be used in face masks, e.g., breathing masks, in order toprovide a tight and comfortable contact between mask and a user.

Other aspects, features, and advantages of this invention will becomeapparent from the following detailed description when taken inconjunction with the accompanying drawings, which are a part of thisdisclosure and which illustrate, by way of example, principles of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings facilitate an understanding of the variousembodiments of this invention. In such drawings:

FIG. 1 is a schematic view of a production line according to anembodiment of a method of the present invention;

FIG. 2 is a cross-sectional view of an open hollow structure accordingto an embodiment of the present invention;

FIG. 3 is a cross-sectional view of an open hollow structure placed on atool for holding the open hollow structure according to an embodiment ofthe present invention;

FIG. 4 is a cross-sectional view of an open hollow structure placed on atool for holding the open hollow structure when the filler medium isfilled into the open hollow structure according to an embodiment of thepresent invention;

FIG. 5 is a cross-sectional view of a filled open hollow structureaccording to an embodiment of the present invention;

FIG. 6 a is a cross-sectional view of the closing or sealing area of anopen hollow structure clamped by clamping means providing a cavityaccording to an embodiment of the present invention;

FIG. 6 b is an enlarged view of a portion of FIG. 6 a;

FIG. 7 a is a cross-sectional view of a second step of the closing stepshowing the tool, hollow structure and clamping means wherein the cavityis filled with a material for closing the open hollow structureaccording to an embodiment of the present invention;

FIG. 7 b is an enlarged view of a portion of FIG. 7 a;

FIG. 7 c is an isolated view of a filled and closed hollow structureaccording to an embodiment of the present invention;

FIG. 8 is a cross-sectional view of a curing step according to anembodiment of the present invention;

FIG. 9 is a cross-sectional view of the closed hollow structure beingremoved from the tool after completion of the method according to anembodiment of the present invention;

FIG. 10 is a cross-sectional view of a filled hollow structure accordingto an embodiment of the present invention;

FIG. 11 a is a cross-sectional view of a hollow structure wherein theclosing area is designed as a bi-stable membrane according to anembodiment of the present invention, the bi-stable membrane in an openposition;

FIG. 11 b is a cross-sectional view of the hollow structure shown inFIG. 11 a showing the bi-stable membrane in a closed and sealedposition; and

FIG. 12 is a perspective view of an automated production line accordingto an embodiment of the invention.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

The following description is provided in relation to several embodimentswhich may share common characteristics and features. It is to beunderstood that one or more features of any one embodiment may becombinable with one or more features of the other embodiments. Inaddition, each single feature or combination of features in any of theembodiments may constitute an additional embodiment.

In this specification, the word “comprising” is to be understood in its“open” sense, that is, in the sense of “including”, and thus not limitedto its “closed” sense, that is the sense of “consisting of”. Acorresponding meaning is to be attributed to the corresponding words“comprise”, “comprised” and “comprises” where they appear.

FIG. 1 is a schematic view of a method for producing a filled hollowstructure according to an embodiment of the present invention. Inparticular, arrows A, B and C show the way or path of the productaccording to steps of the method according to an embodiment of thepresent invention.

Arrow A indicates the feeding of an open hollow structure to a tool forproducing a filled hollow structure, Arrow B indicates the path orsuccessive and/or simultaneous steps of the hollow structure along thetool for producing a filled hollow structure, and Arrow C illustratesthe removal of the filled hollow structure from the tool. The openhollow structure may be constructed of an injection molded plasticstructure having thin wall thicknesses, e.g., made of silicone (e.g.,liquid silicone rubber). The open hollow structure is inserted from thedirection as indicated by arrow A and positioned on a tool for holdingthe open hollow structure in working position 1. In the illustratedembodiment, working position 1 may be located on a turntable 10 so thatthe open hollow structure may be successively carried along positions 1to 5 on table 10. At each position 1 to 5, one or more method steps maybe carried out according to embodiments of the present invention.

FIG. 2 illustrates an embodiment of an open hollow structure adapted tobe inserted into the tool at position 1. As illustrated, open hollowstructure 20 includes a thin inner wall 22 and a thin outer wall 24wherein a hollow or hollow area 26, such as a pocket or a cavity, isformed between inner wall 22 and outer wall 24. Inner wall 22 and outerwall 24 merge at one end of the structure via a bottom or transitionwall 27. Hollow structure 20 has a basically ring shaped form whenviewed from the bottom in FIG. 2. Hollow structure 20 also includes afilling or sealing area 28 that defines an opening 30 in which thehollow area 26 is open to the environment. In the illustratedembodiment, opening 30 is a circular slot extending between a firstclosing area 32 and a second closing area 34. Closing areas 32 and 34may be designed as flattened, basically ring-shaped portions of thehollow structure which are able to close the open hollow structure,e.g., when abutting each other in mutual contact. As illustrated,closing area 32 forms part of or is directly or indirectly connected toinner wall 22 whereas closing area 34 forms part of or is directly orindirectly connected to outer wall 24. As shown in FIG. 2, closing orsealing area 28 and hollow structure 20 have a substantially circularform. However, the hollow structure and/or the closing area of thehollow structure is not limited to circular or substantially circularshapes, but may have other suitable forms and shapes as will bediscussed below in further detail. According to an embodiment, thehollow structure and/or the closing area of the hollow structure mayhave the form and/or configuration of face masks for deliveringbreathable air to a patient and/or of hollow cushions of such masks,e.g., a basically triangular form.

FIG. 3 shows the open hollow structure 20 at position 1 (FIG. 1) inwhich the open hollow structure 20 is placed on a tool 50 for holdingthe open hollow structure 20. In the illustrated embodiment, thegeometry of tool 50 substantially conforms to the geometry of the hollowstructure 20 and particularly to the geometry of inner wall 22. Asillustrated, tool 50 comprises a duct 52 and nozzles or channels 57adapted to apply a vacuum and/or compressed air for use in holdinghollow structure 20 on the tool 50 and/or releasing or removing hollowstructure 20 from the tool 50.

FIG. 4 illustrates the hollow structure 20 at working position 2(FIG. 1) in which the open hollow structure 20 is filled with a fillermedium 60, e.g., via injection pin 52. In the illustrated embodiment,injection pin 52 is adapted to be connected to a supply of filler mediumand is adapted to be inserted into the opening 30 of the hollowstructure 20 to provide fluid communication between the supply of fillermedium and the hollow area 26 of hollow structure 20. According to anembodiment, more than one injection pin 52 may be used for fillinghollow structure 20.

FIG. 5 shows the hollow structure 20 filled with a filler medium 60 andisolated from the tool 50. As illustrated hollow area 26 is completelyfilled with filler medium 60 and a remaining cavity or hollow area 38(provided in an intermediate second section 42 (see FIG. 2) of hollowstructure 20 reaching to the closing area 28) is not filled with fillermedium 60. In alternative embodiments, hollow area 26 may be onlypartially filled with filler medium 60 or the cavity or hollow area 38of the intermediate second section of hollow structure 20 may be fullyfilled with filler medium 60.

In an embodiment, e.g., when the filler medium is a gel or a siliconegel, the gel may be inserted cold or at room temperature as a liquid andmay be subsequently heated to cure, as discussed further below.According to a further embodiment, the gel may be inserted into thehollow area 26 preheated. This arrangement allows a faster cure.According to another embodiment, the gel may be inserted pre-cooled intothe hollow area 26. This arrangement slows down the curing process,e.g., if the gel is curing too fast.

As a further step, preceding the filling of the hollow area 26 with afiller medium 60, a vacuum may be supplied to the hollow area 26 inorder to suck air out of the hollow area 26 before the filler medium,such as a gel, is inserted.

Furthermore, the gel may be allowed to only cure partially to achievedesired properties of the structure.

FIGS. 6 a and 6 b illustrate the hollow structure at working position 3(FIG. 1). FIG. 6 a shows hollow structure 20 filled with a filler medium60 and placed on tool 50 wherein a second tool 70 is provided forclosing the filled open hollow structure. In particular, tools 50 and 70are configured to cooperate in a manner so as to close the filled openhollow structure 20. In an embodiment, hollow structure 20 and tool 50are configured such that a third section 44 (see FIG. 2) of hollowstructure 20, i.e., the filling and the closing section 28, is locatedon a closing surface 54 of tool 50. Tool 70 includes a correspondingclosing surface 72 which is adapted to cooperate with tool 50 andparticularly with closing surface 54 of tool 50 so as to allow closingof the filled open hollow structure. In an embodiment, closing surfaces54 and 72 are configured so that when tool 70 is positioned relative totool 50, the tool 70 urges closing area 34 of hollow structure 20towards closing area 32 so that the closing areas 32 and 34 mutuallyabut each other and take a closed position as shown in FIGS. 6 a-6 b.Moreover, tools 50 and 70 and particularly closing surfaces 54 and 72,respectively, provide a cavity 74 in the area of abutting closingsurfaces 32 and 34 of hollow structure 20. As best shown in FIG. 6 b,—cavity 74 surrounds an end portion of closing areas 32 and 34 and thusof hollow structure 20. Particularly, cavity 74 is provided such that itsurrounds the opening 30 (now a closed opening 30) of hollow structure20.

As shown in FIG. 6 a, tool 70 includes a channel system 76 which is influid communication with cavity 74 and is adapted to provide a materialfor closing the open hollow structure to cavity 74. In an embodiment,channel system 76 allows a material for closing the hollow structure 20to be filled into cavity 74, e.g., under pressure. According to analternative embodiment, channel system 76 may be additionally or solelyprovided in tool 50.

FIG. 6 b shows an enlarged view of the area around the cavity 74 and theclosing areas 32 and 34 of hollow structure 20. FIGS. 7 a and 7 b showcavity 74 being filled with a material 80 for closing the hollowstructure 20 in the area of opening 30 and/or closing areas 32 and 34.FIG. 7 c shows the hollow structure 20 without tools 50 and 70, e.g.after completion of filling and closing of the hollow structure.

According to an embodiment, tool 50 and/or tool 70 may be adapted toassist curing of the material for closing the open hollow structure. Forexample, tools 50 and/or 70 may be heatable and/or coolable to allow thematerial 80 filled into cavity 74 to cure.

FIG. 8 illustrates the hollow structure 20 at working position 4(FIG. 1) wherein the filler medium 60 inside the closed and filledhollow structure 20 may be cured. Such curing may be achieved by, e.g.,the application of temperature, radiation, etc. In a embodiment, tool 50may be heatable to assist curing of filler medium 60.

FIG. 9 shows the hollow structure 20 at working position 5 (FIG. 1) inwhich the hollow structure 20 is removed from tool 50, e.g., by applyingpressured air through duct 52 and nozzles 54 and/or by releasing thevacuum applied to hold hollow structure 20 on the tool 50 (e.g.,following filling, closing, and curing of the hollow structure). Thesequence/order of filling, closing, curing, and removing may be changedor simultaneous.

FIG. 10 shows a hollow structure 20 after having been filled with fillermedium 60 and after having been closed in the area of opening 30 in themanner as described above. As illustrated, hollow structure 20 includesthree sections 40, 42, 44. First section 40 comprises cavity 26 filledor to be filled with filler medium 60, third section 44 comprisesopening 30 and closing areas 32 and 34, and second section 42 isarranged between first section 40 and third section 44 and constitutes atransition between first section 40 and third section 44. According toan embodiment, section 42 constitutes or comprises a connectionstructure 29 (also see FIGS. 2-5) suitable for connecting hollowstructure to a superior structure, such as a face mask or a part of aface mask. Alternatively, hollow structure 20 may comprise further meansor structure for allowing or facilitating a connection of hollowstructure 20 to further structures and to allow an assembly of hollowstructure 20 together with further means and structures to become afinal product, such as a face mask.

As shown in FIG. 10, hollow structure 20 may comprise different wallthicknesses as well as various changes in geometry depending on theindividual requirements of the desired use.

FIG. 11 a shows the hollow structure in an unfilled and open state andFIG. 11 b shows the hollow structure in a filled and closed or sealedstate. As discussed above, hollow structure 20 comprises a closableopening 30, e.g., arranged between areas 32 and 34. Areas 32 and 34 maybe constructed as comprising mutual surfaces which when abutting eachother allow the opening 30 of hollow structure 20 to be sealingly closedas discussed above with reference to FIGS. 6 and 7. As shown in FIGS.2-5 and 11 a-11 b, hollow structure 20 includes a bi-stable membrane 36,e.g., in the area of area 34. Bi-stable membrane 36 allows section 34 toassume two stable positions. In this context, the term “stable” refersto positions in which section 34 remains without application ofadditional external forces. When section 34 or bi-stable membrane 36 arein a first, opened position (as shown in FIG. 11 a), hollow structure 20is open and a filler medium 60 may be injected. In a second, closedposition, as shown in FIG. 11 b, section 34 abuts section 32 so thatopening 30 and thus hollow structure 20 are closed. In an embodiment,membrane 36 may be structured so that section 34 may maintain either thefirst or second stable position, e.g., even if section 34 is slightlymoved from the stable position it will tend to return to the respectivestable position. In an exemplary embodiment, only if section 34 travelsa defined way from a stable position towards the other stable position,it will spring or snap to the other stable position after having beenmoved over a point of no return. These effects may be achieved by theprovision of bi-stable membrane 36 which is designed accordingly byvarying its geometry and wall thickness depending on the overallgeometry of opening 30, area 32 and particularly area 34.

At working position 5 as indicated in FIG. 1, the filled, enclosedhollow structure 20 may be removed from the table 10, see arrow C.Subsequently, further method steps may be applied.

FIG. 12 shows a schematic three-dimensional view of a table 10 with fiveworking positions at which tools 50 are provided. A hollow structure 20positioned on a tool 50 at working position 1 may thus undergo therespective method treatments as discussed above by turning table 10 inthe direction of arrow B as indicated in FIG. 1 so that the respectivehollow structure 20 moves from a first working position to a secondworking position, etc. Further means for carrying out the respectivemethod steps are provided at working stations 1′, 2′, 3′, 4′, 5′ outsidethe table 10 and apply the same method steps to different hollowstructures 20 passing the working station after each cycle. Accordingly,referring to FIG. 1, a hollow structure is placed on tool 50 at workingposition 1 adjacent working station 1′, and then the hollow structure ismoved by turning turntable 10 to move working position 1 to workingstation 2′. At the same time, working position 5 moves to workingstation 1′ and a new hollow structure is placed onto respective tool 50at working position 5. At working station 2′, filling of the fillermaterial is carried out. In the next cycle, the hollow structure atworking position 1 moves from working station 2′ to working station 3′where the closing of the hollow structure is performed as discussedabove. At the same time, hollow structure 20 positioned on workingposition 5 moves from working station 1′ to working station 2′. Afterfurther method steps have been performed, i.e., curing at workingstation 4′ and removing the finished hollow structure at working station5′, working position 1 again arrives at working station 1′ and a newhollow structure may be inserted. It is to be noted, as discussed above,that step 4 regarding curing of the inserted filler material may be anoptional step of the method according an embodiment of the presentinvention.

It should be appreciated that the above description as well as thefigures relate to an exemplary embodiment of a method and productaccording to an embodiment of the present invention. However, therespective method as well as the product and tool and in particulartheir geometry should not be considered as being restricted by the aboveexample. According to further embodiments, a hollow structure, may nothave a circular cross section in top and/or bottom views but maycomprise different forms. For example, a hollow structure may have asubstantially triangular form when viewed from the top and/or bottom.However, the hollow structure may also comprise further symmetrical andnon-symmetrical forms in top and/or bottom views such as a rectangular,elliptical, round, ring-shaped and/or linear, etc.

As discussed above, the filler medium may be a fluid such as a gaseousand/or liquid medium, a gel, a powder, beats or pellets, a foam or afoamable medium, etc. In an embodiment, the filler medium may bestructured to allow the hollow structure to yield or react resilientlyupon application of external pressure and provide a soft and comfortabledeformable appearance. The softness or hardness of the filler medium orthe filled hollow structure may be adapted according to the requirementsof the desired use either during production of the filled hollowstructure or after production and prior to use. This may be establishedby either adjusting the geometry and wall thicknesses of the hollowstructure to adjust the general support of the filler medium, adjustingthe degree up to which the hollow area is filled with the filler medium,adjusting the filler medium itself, as well as a combination of thesefactors. For example, the hollow structure may comprise different wallthicknesses and/or structures for fulfilling additional objects and/orthe like.

In an embodiment, the hollow structure comprises a connection thatallows a vacuum to be applied to the hollow area, thereby allowing thevacuum to deform the hollow structure so that a desired shape may beachieved and maintaining the vacuum in the hollow area after closure ofthe respective connection so that the shape of the hollow structure maybe maintained. Further, a desired shape or individual shape may beformed and fixed by, e.g., a curing process of the filler medium. In anembodiment, the filler medium and thus the filled hollow structure maystill be deformable and soft to a certain degree even after fixation ofa desired shape as discussed above. For example, the hollow structure aswell as the filling may be at least partially flexible and/or may bebrought into a flexible condition.

In an embodiment, the hollow structure may be made of a siliconematerial, e.g., liquid silicone rubber, and the filler medium may alsobe made of a silicone material, e.g., liquid silicone rubber, in asubstantially liquid aggregate state (e.g., such as gel) which may beachieved by partial curing or adding additives.

While the invention has been described in connection with what arepresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the invention. Also, the various embodiments described abovemay be implemented in conjunction with other embodiments, e.g., aspectsof one embodiment may be combined with aspects of another embodiment torealize yet other embodiments. Further, each independent feature orcomponent of any given assembly may constitute an additional embodiment.In addition, while the invention has particular application to patientswho suffer from OSA, it is to be appreciated that patients who sufferfrom other illnesses (e.g., congestive heart failure, diabetes, morbidobesity, stroke, bariatric surgery, etc.) can derive benefit from theabove teachings. Moreover, the above teachings have applicability withpatients and non-patients alike in non-medical applications.

What is claimed is:
 1. A method for producing a filled hollow structureof a breathing mask, comprising: producing an injection-molded openhollow structure of a first material; positioning the open hollowstructure on a tool adapted to hold the open hollow structure; fillingthe open hollow structure with a filler medium while the hollowstructure is positioned on the tool; closing the filled open hollowstructure with a second material while the hollow structure ispositioned on the tool; and curing the second material when the secondmaterial is in a different state than the first material, wherein thesecond material is an elastomer, and wherein an end portion of thehollow structure forms a contact zone configured to rest against apatient's face.
 2. A method according to claim 1, wherein the firstmaterial is silicone.
 3. A method according to claim 1, wherein thesecond material is silicone, liquid silicone rubber (LSR), orthermoplastic elastomer (TPE).
 4. A method according to claim 1, whereinthe second material comprises silicone, liquid silicone rubber (LSR),thermoplastic elastomer (TPE), and/or the first material.
 5. A methodaccording to claim 1, wherein the filler medium is a fluid, gas, liquid,foam, expandable fluid, powder and/or gel.
 6. A method according toclaim 1, further comprising at least partially curing the filler medium.7. A method according to claim 1, further comprising removing the hollowstructure from the tool.
 8. A method according to claim 7, wherein thehollow structure is removed from the tool using compressed air.
 9. Amethod according to claim 1, wherein the open hollow structure is heldon the tool by application of compressed air and/or vacuum.
 10. A methodaccording to claim 1, wherein the second material is filled into thecavity under pressure or vacuum.
 11. A method according to claim 1,further comprising closing the filled open hollow structure by clampingjaws that are adapted to provide a cavity, and filling the cavity withthe second material adapted to close the open hollow structure.
 12. Amethod according to claim 11, wherein the jaws are heated or cooled forcuring the second material.
 13. A method according to claim 1, furthercomprising providing the hollow structure with further structures toform a breathing mask.
 14. A method according to claim 1, wherein thehollow structure is completely or partially filled with the fillermedium.
 15. A method according to claim 1, wherein the hollow structureis provided with a connection structure adapted to connect the hollowstructure to a further structure.
 16. A method according to claim 1,wherein the hollow structure comprises a connection adapted to allow avacuum or pressure to be applied to the hollow structure.
 17. A methodaccording to claim 1, wherein the filler medium stores heat and/or cold.18. A method according to claim 1, wherein the filler medium is adaptedto harden and/or soften upon a trigger signal.
 19. A method according toclaim 18, wherein the trigger signal is a crystallization signal or anapplication of heat or cold.
 20. A method according to claim 1, whereinthe hollow body includes a bi-stable membrane.
 21. A method according toclaim 1, wherein the hollow structure is a cushion for a breathing mask.22. The method according to claim 1, wherein the step of producing anopen hollow structure occurs before the step of positioning the openhollow structure.
 23. The method according to claim 1, wherein the stepof filling the hollow structure includes filling the hollow structuresuch that a first area of the hollow structure is filled with the fillermaterial and a second area of the hollow structure is not filled withthe filler material.
 24. The method according to claim 1, wherein theend portion is configured to seal against the patient's face.
 25. Amethod according to claim 1, wherein the second material is not asilicone glue or a silicone adhesive.
 26. A method according to claim 1,wherein the hollow structure includes a first section, a second sectionand a third section, and wherein the first section has a first hollowarea which is filled with the filler medium, the third section has anopening which is closed by the second material, and the second sectionis arranged between the first section and the third section and includesa second hollow area.
 27. A method according to claim 26, wherein thesecond hollow area is filled with the filler medium.
 28. A methodaccording to claim 26, wherein the second hollow area is not filled withthe filler medium.
 29. A method according to claim 1, wherein the hollowstructure has an inner wall and an outer wall, each of the inner walland the outer wall includes a respective closing area, wherein saidclosing step includes abutting in mutual contact the respective closingareas and subsequently providing the second material into a cavity thatsurrounds an end portion of the abutted closing areas.
 30. A method forproducing a filled hollow structure of a breathing mask, comprising:producing an open hollow structure of a first material; positioning theopen hollow structure on a tool adapted to hold the open hollowstructure; filling the open hollow structure with a filler mediumthrough at least one opening; and closing the opening, wherein thehollow structure includes a bi-stable membrane that is movable between afirst position in which the opening is open and a second position inwhich the opening is closed.
 31. The method according to claim 30,wherein the bi-stable membrane, in the second position, causes a portionof the hollow structure to collapse to close the opening.
 32. The methodaccording to claim 30, wherein an end portion of the hollow structureforms a contact zone configured to rest against a patient's face. 33.The method according to claim 32, wherein the end portion is configuredto seal against the patient's face.